/* * Copyright (c) 2006-2021, RT-Thread Development Team * Copyright (c) 2019-Present Nuclei Limited. All rights reserved. * * SPDX-License-Identifier: Apache-2.0 * * Change Logs: * Date Author Notes * 2020/03/26 Huaqi Nuclei RISC-V Core porting code. */ #include #include #include #include #include "cpuport.h" #define SYSTICK_TICK_CONST (SOC_TIMER_FREQ / RT_TICK_PER_SECOND) /* Interrupt level for kernel systimer interrupt and software timer interrupt */ #define RT_KERNEL_INTERRUPT_LEVEL 0 /* Initial CSR MSTATUS value when thread created */ #define RT_INITIAL_MSTATUS (MSTATUS_MPP | MSTATUS_MPIE | MSTATUS_FS_INITIAL) /** * @brief from thread used interrupt context switch * */ volatile rt_ubase_t rt_interrupt_from_thread = 0; /** * @brief to thread used interrupt context switch * */ volatile rt_ubase_t rt_interrupt_to_thread = 0; /** * @brief flag to indicate context switch in interrupt or not * */ volatile rt_ubase_t rt_thread_switch_interrupt_flag = 0; /** * @brief thread stack frame of saved context * */ struct rt_hw_stack_frame { rt_ubase_t epc; /*!< epc - epc - program counter */ rt_ubase_t ra; /*!< x1 - ra - return address for jumps */ rt_ubase_t t0; /*!< x5 - t0 - temporary register 0 */ rt_ubase_t t1; /*!< x6 - t1 - temporary register 1 */ rt_ubase_t t2; /*!< x7 - t2 - temporary register 2 */ rt_ubase_t s0_fp; /*!< x8 - s0/fp - saved register 0 or frame pointer */ rt_ubase_t s1; /*!< x9 - s1 - saved register 1 */ rt_ubase_t a0; /*!< x10 - a0 - return value or function argument 0 */ rt_ubase_t a1; /*!< x11 - a1 - return value or function argument 1 */ rt_ubase_t a2; /*!< x12 - a2 - function argument 2 */ rt_ubase_t a3; /*!< x13 - a3 - function argument 3 */ rt_ubase_t a4; /*!< x14 - a4 - function argument 4 */ rt_ubase_t a5; /*!< x15 - a5 - function argument 5 */ #ifndef __riscv_32e rt_ubase_t a6; /*!< x16 - a6 - function argument 6 */ rt_ubase_t a7; /*!< x17 - s7 - function argument 7 */ rt_ubase_t s2; /*!< x18 - s2 - saved register 2 */ rt_ubase_t s3; /*!< x19 - s3 - saved register 3 */ rt_ubase_t s4; /*!< x20 - s4 - saved register 4 */ rt_ubase_t s5; /*!< x21 - s5 - saved register 5 */ rt_ubase_t s6; /*!< x22 - s6 - saved register 6 */ rt_ubase_t s7; /*!< x23 - s7 - saved register 7 */ rt_ubase_t s8; /*!< x24 - s8 - saved register 8 */ rt_ubase_t s9; /*!< x25 - s9 - saved register 9 */ rt_ubase_t s10; /*!< x26 - s10 - saved register 10 */ rt_ubase_t s11; /*!< x27 - s11 - saved register 11 */ rt_ubase_t t3; /*!< x28 - t3 - temporary register 3 */ rt_ubase_t t4; /*!< x29 - t4 - temporary register 4 */ rt_ubase_t t5; /*!< x30 - t5 - temporary register 5 */ rt_ubase_t t6; /*!< x31 - t6 - temporary register 6 */ #endif rt_ubase_t mstatus; /*!< - machine status register */ }; /** * This function will initialize thread stack * * @param tentry the entry of thread * @param parameter the parameter of entry * @param stack_addr the beginning stack address * @param texit the function will be called when thread exit * * @return stack address */ rt_uint8_t *rt_hw_stack_init(void *tentry, void *parameter, rt_uint8_t *stack_addr, void *texit) { struct rt_hw_stack_frame *frame; rt_uint8_t *stk; int i; stk = stack_addr + sizeof(rt_ubase_t); stk = (rt_uint8_t *)RT_ALIGN_DOWN((rt_ubase_t)stk, REGBYTES); stk -= sizeof(struct rt_hw_stack_frame); frame = (struct rt_hw_stack_frame *)stk; for (i = 0; i < sizeof(struct rt_hw_stack_frame) / sizeof(rt_ubase_t); i++) { ((rt_ubase_t *)frame)[i] = 0xdeadbeef; } frame->ra = (rt_ubase_t)texit; frame->a0 = (rt_ubase_t)parameter; frame->epc = (rt_ubase_t)tentry; frame->mstatus = RT_INITIAL_MSTATUS; return stk; } /** * @brief Do rt-thread context switch in interrupt context * * @param from thread sp of from thread * @param to thread sp of to thread */ void rt_hw_context_switch_interrupt(rt_ubase_t from, rt_ubase_t to) { if (rt_thread_switch_interrupt_flag == 0) rt_interrupt_from_thread = from; rt_interrupt_to_thread = to; rt_thread_switch_interrupt_flag = 1; RT_YIELD(); } /** * @brief Do rt-thread context switch in task context * * @param from thread sp of from thread * @param to thread sp of to thread */ void rt_hw_context_switch(rt_ubase_t from, rt_ubase_t to) { rt_hw_context_switch_interrupt(from, to); } /** * @brief shutdown CPU * */ RT_WEAK void rt_hw_cpu_shutdown() { rt_uint32_t level; rt_kprintf("shutdown...\n"); level = rt_hw_interrupt_disable(); while (level) { RT_ASSERT(0); } } /** * @brief Do extra task switch code * * @details * * - Clear software timer interrupt request flag * - clear rt_thread_switch_interrupt_flag to 0 */ void rt_hw_taskswitch(void) { /* Clear Software IRQ, A MUST */ SysTimer_ClearSWIRQ(); rt_thread_switch_interrupt_flag = 0; } /** * @brief Setup systimer and software timer interrupt * * @details * * - Set Systimer interrupt as NON-VECTOR interrupt with lowest interrupt level * - Set software timer interrupt as VECTOR interrupt with lowest interrupt level * - Enable these two interrupts */ void rt_hw_ticksetup(void) { uint64_t ticks = SYSTICK_TICK_CONST; /* Make SWI and SysTick the lowest priority interrupts. */ /* Stop and clear the SysTimer. SysTimer as Non-Vector Interrupt */ SysTick_Config(ticks); ECLIC_DisableIRQ(SysTimer_IRQn); ECLIC_SetLevelIRQ(SysTimer_IRQn, RT_KERNEL_INTERRUPT_LEVEL); ECLIC_SetShvIRQ(SysTimer_IRQn, ECLIC_NON_VECTOR_INTERRUPT); ECLIC_EnableIRQ(SysTimer_IRQn); /* Set SWI interrupt level to lowest level/priority, SysTimerSW as Vector Interrupt */ ECLIC_SetShvIRQ(SysTimerSW_IRQn, ECLIC_VECTOR_INTERRUPT); ECLIC_SetLevelIRQ(SysTimerSW_IRQn, RT_KERNEL_INTERRUPT_LEVEL); ECLIC_EnableIRQ(SysTimerSW_IRQn); } /** * systimer interrupt handler eclic_mtip_handler * is hard coded in startup_.S * We define SysTick_Handler as eclic_mtip_handler * for easy understanding */ #define SysTick_Handler eclic_mtip_handler /** * @brief This is the timer interrupt service routine. * */ void SysTick_Handler(void) { /* Reload systimer */ SysTick_Reload(SYSTICK_TICK_CONST); /* enter interrupt */ rt_interrupt_enter(); /* tick increase */ rt_tick_increase(); /* leave interrupt */ rt_interrupt_leave(); } /** * @brief Disable cpu interrupt * * @details * * - Disable cpu interrupt by clear MIE bit in MSTATUS * - Return the previous value in MSTATUS before clear MIE bit * * @return the previous value in MSTATUS before clear MIE bit */ rt_base_t rt_hw_interrupt_disable(void) { return __RV_CSR_READ_CLEAR(CSR_MSTATUS, MSTATUS_MIE); } /** * @brief Restore previous saved interrupt status * * @param level previous saved MSTATUS value */ void rt_hw_interrupt_enable(rt_base_t level) { __RV_CSR_WRITE(CSR_MSTATUS, level); }